public string ReadAsString()
{
string s = "";
switch (mode)
{
case UltraSonicMode.Centimeter:
s = Read().ToString() + " cm";
break;
case UltraSonicMode.Inch:
s = Read().ToString() + " inch";
break;
case UltraSonicMode.Listen:
s = Read().ToString();
break;
}
return s;
}